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You Are Not Alone: How Human Gut Biomes Have Evolved Along With Us

Jenna Luecke
University of Texas at Austin
A recent study, led by UT Austin integrative biologist Howard Ochman, found that human gut microbes have evolved along with us.

As humans have evolved, so has the bacteria that lives inside us.

That’s according to a recent study out of UT Austin, which indicates that the bacteria living in humans’ guts has co-evolved along with our species – so what you’ve heard referred to as “good bacteria” could easily be referred to instead as just “human bacteria.”

And, researchers say, that means we should be careful not to throw it off balance.

We’ve known for a while how much we rely on the bacteria in our guts to help us digest our food; without them we couldn’t process key vitamins, or even digest plants properly. But researchers have genetically mapped the lineage of gut microbes, in humans and the other great apes, and what they’ve discovered is something that binds us even closer to these microbes. Evolutionary biologist Alex Georgiev is one of the researchers who worked on the study.

“The organisms living in our guts and in the guts of those apes, they have their own lineage, going back to approximately 15 million years ago,” he said. “And the way they have diverged from their common ancestor maps really neatly on the evolutionary tree of the great apes and us, of hominids.”

Our gut microbes have been co-evolving with us for millions of years. And as we’ve broken away from our ancestors, so have these bacteria. In fact, they’ve actually been shaping how our own guts have evolved along the way.

So what does this mean for us? For one, said Cornell microbiologist Esther Angert, it means that our internal ecosystem is more fragile than previously thought.

“You know,” she said, “it’s possible that, if we lose a lineage because we’re using so many antibiotics and exposing kids to antibiotics early on, we might be losing these important partnerships.”

The long-term effects of human behavior on our gut-biomes aren’t yet known. But Angert said that, if there are changes to our gut-biome, they may be contributing to the obesity epidemic.

While we can’t forgo antibiotics altogether, we can try to minimize their use. One way is by avoiding meat from animals raised using antibiotics. And the next time you’re sick, Angert said, just ride it out – unless your doctor is absolutely sure it’s not a virus. Your gut will appreciate it.